Just a query regarding the aether gems that cost 50 dingbats to buy - When they say "HARVEST commodities at the end of the month", does it refer to an RL month or a lusternian month?

It gets a little confusing how RL and lusternian months seem to be used interchangably in some areas.

lusternia month (and not the weave, the actual calendar month)

That means every 25 RL hours, yeah.

And it's actually after the beginning of the month.

Oh, one last question, Does installing a gem require an entirely empty room? (as in no furniture installed, etc?)

No, they don't actually take up any space in the room, so furniture doesn't matter. But you can only have one mine per room.

You can even combine these with other gems like willpower or stasis, or functions like a manse stable.